A mathematical model was established to describe the behavior of molten steel jet flow and steel/slag interface fluctuation with EMBR ruler.The effects of different electromagnetic parameters on the behavior of molten steel jet flow and steel/slag interface fluctuation were investigated by numerical simulation.The influence of magnetic induction intensity

the change of distance between the level electromagnetic pole and submergence depth of SEN was analyzed on the behavior of molten steel jet flow and steel/slag interface fluctuation.The results reveal that the application of EMBr ruler can control effectively the molten steel jet flow

and reduce the velocity of upward backflow and downward backflow as well as stabilizing the fluctuation of molten steel and liquid slag interface when the electromagnetic field of EMBr ruler coveres the jet flow impact region

upward backflow and downward backflow zone（D=20 mm）at the same time.For a long distance between the level electromagnetic pole and submergence depth of SEN（D=220 mm）

the molten steel velocity of upward backflow in the mold can′t be depressed by increasing the magnetic induction intensity.A higher magnetic induction intensity isn’t conductive to stabilize the fluctuation of molten steel and liquid slag interface

and the probability of slag entrapment is increased.